My grandmother is in her 90s; recently her three-year-old microwave broke due to a power surge caused by a winter storm. She was going to have the microwave put out at the curb. When my dad found out he insisted on taking it back to the retailer where it was purchased. This is a large, well-known store with a policy that goods can be returned if the customer isn’t satisfied; they took it back without question. So my query: since the appliance broke as a result of a power surge and not any manufacturing defect, is it ethical to take it back for refund?

My first inclination was “obviously it’s wrong,” but on (sort of) sober second thought, I’m less certain.

A warranty has obligations on both sides. The manufacturer or retailer or both is obligated to repair/replace any widget that fails do its job for a specified period of time. Most warranties have specific limits, and legislation often defines what those restrictions can be.

The purchaser also has obligations. First, the consumer is expected to maintain the widget according to schedules, standards and procedures specified by the manufacturer. In the case of an automobile, for example, carmakers have specific service schedules; to maintain warranty protection, consumers are expected to change the oil, filters and so on as specified.

Second, a consumer is only permitted, under most warranties, to use the device for the purpose for which it was intended. If grandma used her microwave to dry her rain-soaked cat, for example, it would be unreasonable to expect the manufacturer to extract fur-balls from the fan.

In your case, however, this gets a little tricky. To start with, three years is a very long warranty period; presumably, however, the retailer saw the receipt and knew when it was purchased. If a retailer is willing to take it back after such a length of time, good for him — you’ll shop there in the future. It’s a large part of why I buy hats from Tilley and everything else from Canadian Tire.

The power surge is another issue. If the device in question were a piece of electronics — a computer, TV or the like — then the “reasonable maintenance” provision in many warranties would require it to be plugged into a surge suppressor. Every piece of electronics I’ve bought recently comes with a warning about the importance of such a device; so if we were talking computer, grandma’s baked Apple would be her tough luck.

But no one plugs a microwave into a surge suppressor; you plug it straight into a kitchen outlet. I live in the country and I have a 20-year-old microwave, plugged straight into the wall, that has never skipped a beat. Surely a microwave bought three years ago should work as well as one bought in the last millennium.

Whether a retailer chooses to take it back after three years is, ultimately, a matter of customer relations, not legal obligation. But a microwave should survive the odd power surge, and as long as there’s no misrepresentation, there’s nothing wrong with asking the maker or retailer to make good when it doesn’t.